WRS PAK68/3 User manual

Processor Replacement Card, Version 3
CPU Accelerator for the Atari ST(E) Series
© 2003 WRS Software-Design, Humboldtstrasse 12, 45886 Gelsenkirchen

IMPRINT
Page 1 PAK68/3
PAK68/3
Processor Replacement Card, Version 3
CPU Accelerator for the Atari ST(E) Series
Developer: Holger Zimmermann
Copyright © 2003 WRS Software-Design
All Rights Reserved. The copyright to the hardware extension
PAK68/3, including the GAL equations, lies with the developers.
Reproduction is permitted for private use only!
Distributor/Supplier:
WRS Software-Design
W. Rohmann & R. Skuplik GbR
Humboldtstrasse 12
45886 Gelsenkirchen
TEL: 0209 - 87 30 01
FAX: 0209 - 87 30 02
E-Mail: [e-mail]
WWW: http://www.wrsonline.de
Documentation: R. Skuplik, H. Zimmermann
2nd Edition from 01/11/2000
Limitation of Liability
We reserve the right to make changes to the hardware, the
GAL equations or the documentation withhout restriction. We
are not responsible for the accuracy of the manual or damage
resulting from the use of the hardware. Every modification
done to your own computer system is performed at your own
risk!
We are always grateful for suggestions to improve the manual.

Table of Contents
PAK68/3 Page 2
Table of Contents
1. Before Starting 3
1.1 Notes 3
1.2 Delivery Options 3
1.3 Requirements 3
1.4 Features of the PAK68/3-030 5
2. Building the PAK68/3 5
2.1 Prerequisites 5
2.2 Clock Buffering –Part 1 6
2.3 The Construction 7
3. Installing the PAK68/3 8
3.1 Preparing the Mainboard 8
3.2 Preparing the PAK 11
3.3 Installing the PAK 12
3.4 Initial Testing 12
4. Configuring the PAK68/3 13
4.1 The GAL Set 13
4.2 The Jumpers 14
4.3 The TOS 15
4.4 Clock Buffering - Part 2 16
4.5 PAK and 68000: Alternate Operating Mode 17
4.6 PAK with Mainboard Clock Greater Than 8MHz 18
4.7 PAK and PuPla/? 19
5. Troubleshooting 19
5.1 Startup Problems 20
5.2 Stability Problems 20
5.3 DMA/Floppy Problems 21
5.4 Additional Extensions 22
Appendix
A Component Layout 24
B Parts List 25
C TOS ROM Table 26

1. Before Starting
Page 3 PAK68/3
1. Before Starting
1.1 Notes
Please read the instructions carefully before you begin the
construction and installation. Most errors can be attributed to an
insuffucient knowledge of the instructions. The installation of the
finished PAK68/3 board should be possible even for people with
limited hardware experience. If the necessary steps seem too
difficult, ask an acquaintance with some experience or contact
us (see imprint).
Then again, anyone with the empty board or the parts kit
shouldn't really face any great hurdles. The required steps are
of medium difficulty so you should already have some
experience with the construction and installation of circuit
boards. The construction and installation of the PAK68/3 as
well as changes to your computer are performed at your own
risk.
The PAK68/3 was first introduced in the magazine c’t. If you
would like to read the articles they were in the 11/93 issue page
222 and the 12/93 issue page 276.
1.2 Delivery Options
The PAK68/3 is available in three versions; each with manual
and disk.
Empty board with optional programmed GALs
Parts Kit (Empty board and hard to procure components)
Ready-Built Unit
optional:
PAK-GAL Set P13-50d, P2-ST, P3-PUK-A, V4-50ac,
V5-51a, P6-ST (for operation without FRAK/?) or P6-
F05 (for operation with FRAK/?). (GAL combinations at
the time of the printing of the manual)
1.3 Requirements
The PAK is a very stable and trouble-free CPU accelerator but
there are a few things to keep in mind:

1.3 Requirements
PAK68/3 Page 4
The PAK is designed to work only in 68000 based systems:
i.e. not in the TT, Falcon or Clones.
The target CPU package is DIP (64pin, rectangular). For
PLCC-CPUs (STE, MSTE; 68pin, square) an adapter is
needed since the PAK expects the CPU in DIP form.
Unfortunately, this is a very problematic issue, since there are
always problems with plug-type adapters. Therefore, we do
not recommend installing the PAK in systems with PLCC-CPU.
The CPU must already be socketed otherwise the PAK cannot
be plugged in. If someone wants to use the 68000 CPU in
alternate operating mode it can be used later on the PAK
(together with the switchover GAL P3). The PAK cannot be
installed onto an existing 68000 CPU!
If a blitter is present it is best to completely remove it or at
least disable it since it impedes the operation of the PAK.
Incidentally, the PAK offers the speed benefits of the blitter
anyway since it overtakes the performance of the blitter from
32MHz onwards.
For the proper operation of the PAK a patched TOS 3.06 is
necessary in EPROMs located on the PAK board. Without this
PAK-TOS, if the PAK runs at all, it is very limited (because the
PMMU of the 68030 is not initialized).
The mainboard RAM should have a maximum access time of
100ns with 80ns being better and 60ns being optimal.
Unfortunately, there are add-ons with 120ns and even 150ns.
With those you will inevitably have problems (random
crashes).
If you run a TOS-Card (TOS 2.06 upgrade), you must check
that the access time of any GALs present on the extension
do not exceed 15ns. Unfortunately if the GAL used is slow
(25ns for example), you must remove the TOS-card (or
install a faster GAL).
When the PAK is used with a MegaSTE make sure to set the
processor clock to 8MHz and turn off the board cache
(remember to save the settings) otherwise the PAK will not
work.

1.3 Requirements
Page 5 PAK68/3
You must ensure that the power supply is not overloaded if
you operate the PAK in conjunction with other extensions.
The original power supply is generally not very strong.
It is important to provide solid ground connections (short and
thick). The PAK provides several connection points for this
on the board (GND). Also a direct power connection to the
+5V pad on the PAK is not a bad idea.
IDE adapters can cause problems in principle so it may be
better to use SCSI.
Unfortunately, some graphics adapters can cause problems.
Candidates for this are the NOVA adapters, the VOFA and
the Multiboard. More on this later.
1.4 Features of the PAK68/3-030
68030 processor, 32-bit instruction and data cache on-chip,
PMMU
68881/882 FPU (optional)
32KB second level cache (optional)
32-50 MHz clock frequency
EPROMs with a custom TOS 3.06 on the PAK (optional)
Switchover mode to operate with a 68000 CPU (optional)
High compatibility with Atari mainboards and other hardware
through a clean bus interface (the PAK even runs on 68000-
based Macintosh systems!)
2. Building the PAK68/3
2.1 Prerequisites
This chapter isn't relevant to owners of the finished device. If
this applies please continue reading from Chapter 3 onwards.
We assume that the empty board has been purchased by
persons who know what they are doing and can get the
components themselves. Those who have purchased the
(partial) parts kit still need the remaining components. These
should be available at any well-stocked local electronics store.

2.1 Prerequisites
PAK68/3 Page 6
A good electronics soldering iron (regulated, max. 25W) and a
good desoldering pump should be on-hand. Also, if necessary,
some desoldering braid. Of course you will need flux-cored
electronics solder and a fine side-cutter. If any step in the
process seems too daunting then just ask a friend with some
experience for help or take advantage of our installation service
if all else fails.
If you want to build the PAK yourself then please take great care
in the construction since the board is a 4x multilayer PCB and
errors may be difficult to find after-the-fact and can be costly.
2.2 Clock Buffering - Part 1
Before you start building you will need to decide in principle if
you want to use clock buffering or not. This is because additional
components are required for buffering as well as some standard
components being changed. So you can save time with a little
extra effort and consideration. Though you can always retrofit or
remove the clock buffering later, it's just extra work that can be
avoided.
To help you make the decision here is an overview of the
possibilities:
No Clock Buffering
This really only makes sense if you intend to install a FRAK/?
in the near future since the clock buffering is built-in and so it is
not used on the PAK even if it is installed! Otherwise you can
only do without buffering on a 32 MHz PAK and cannot use a
FPU.
So now if you have decided against clock buffering then you
should close the bridge between R47 and the quartz oscillator
with some solder immediately so you do not forget; otherwise
the PAK will not run since clearly there will be no clock.
Clock Buffering - Permanently Soldered
If you will use the PAK long-term without equipping a FRAK/?
Then we generally recommend clock buffering for the PAK
above 32MHz and always with a FPU (at 50MHz it is

2.2 Clock Buffering –Part 1
Page 7 PAK68/3
pretty much mandatory!). So you will need to obtain the
additional/other components for the clock buffering and
equip the PAK accordingly during construction.
Attention! With FRAK/? the clock buffering must not be used!
Clock-Buffering - Variable
If you intend to play around with the clock buffering (tests
with/without FRAK/?, fiddling with the clock frequency, etc.),
you should consider whether or not to use solder cups for the
analog components of the clock buffering to make it easier to
replace those components at a later time. The same applies
to R41 and R43 if you intend to experiment with the board
clock.
Attention! With FRAK/? the clock buffering must not be used!
2.3 The Construction
Regarding the order of construction we recommend first placing
the flat components i.e. all the analog components such as
resisitors, capacitors and the resistor network. Then solder the
74F86, the four cache SRAMs and the 16V8-GAL P3-PUK-A
directly to the board (without socket). Now place the IC sockets
and the IC plug adapter pins; (using a 64-pin socket below
these can serve as a positioning aid). The board-edge pads of
the two 64-pin SIL rows are for one socket of the PAK (U7, i.e.
for a 68000) and the board-center pads are for the IC adapter
pins for plugging into the mainboard socket (CON2). By the
way, it is best to place the IC adapter pins on the PAK first then
the SIL strips. Now all that remains are the jumper pin headers
and the semiconductor ICs which will be placed into their
sockets just before installation. The jumpers are explained in
more detail in Chapter 4.2.
If you have decided to buffer the clock, solder the 74F00 on the
solder side without a socket. Pin 1 has a square pad. For R47
use 10 ohms instead of 33 ohms. For R48 use 68 ohms and for
C43 use 220pF (between GAL sockets) Also, in this case, the
solder bridge between R47 and the oscillator on the bottom
must remain open.

2.3 The Construction
PAK68/3 Page 8
Attention! With a FRAK/? the clock buffering must not be used!
The PAK should now be soldered except for any possible wires
or cabling. We are moving closer to the installation in Chapter 3.
3. Installing the PAK68/3
3.1 Preparing the Mainboard
To start with: The ideal target system for a PAK is a MegaST.
With the 520ST and 1040ST(F) there are sometimes problems
due to the older board design (keyword: bus terminations) and
the power supply. With the 1040STE and MegaSTE the PLCC
CPU can be a stumbling block since most PLCC-to-DIP
adapters are apt to be problematic.
The important thing is that the CPU must be socketed for the
installation of the PAK since it is placed in leiu of the original
CPU. However, with the switchover GAL P3 on the PAK, a
68000 can be used as a fallback alternative. With this being
said, if your CPU is not socketed now is the time to do it. The
best way to do this is to use a fine side-cutter and snip the CPU
pins close to the mainboard. This renders the CPU unusable,
but a new CPU costs just 10,- DM. A new mainboard would be
much more expensive if you were to require one. After snipping
the pins, you can simply hold each pin remaining in the
mainboard with some tweezers and easily unsolder them. Then
clean the holes with a desoldering pump. (tip: heat from the
component side and suction from the solder side!) and finally
clear the board of any solder blobs or solder splashes remaining
from the desoldering process. Now you are just missing the DIP
precision socket. Please pay attention to the correct alignment
of the socket in relation to the mainboard stenciling. If there was
a small board present on the CPU (only MegaST and you can
just get rid of it with the CPU) you have to close the cut trace
made by Atari on the solder side of the mainboard. To do this,
run one wire from pin 12 of the CPU socket to pin 12 of the
Megabus connector on the bottom of the board.

3.1 Preparing the Mainboard
Page 9 PAK68/3
Using a new CPU to functionally test the new socket wll ensure
the conversion was successfully completed.
If you intend to convert a 1040STE or MegaSTE for the PAK
then you must first remove the CPU from its socket, install a
PLCC-to-DIP adapter then get a 68000 CPU in DIP form to test
it with. But you should be clear that we warn against contact
problems when using a PLCC-to-DIP adapter.
For trouble-free operation of the PAK we strongly recommend
removal of the blitter if it is installed (i.e. MegaST). The reason
is a bus transfer protocol error that can lead to crashes or DMA
issues (which is the reason for the small add-on board in some
MegaSTs). Apart from that, using the blitter in concert with a
PAK will incur a speed penalty: The blitter is a DMA device so
with every blitter activity the second level cache of the PAK is
cleared which effectively slows things down. Regarding working
speeds, the PAK outperforms the blitter anyway from 32MHz
onwards. So if you do decide to remove the blitter, please do
not forget the two solder bridges, so the computer doesn't hang
the next time you turn it on.
So that there are no problems with the mainboard RAM, it
should have a max access time of 100ns. Unfortunately there
are configurations with 120ns or even 150ns. If that is the case
there will certainly be problems. If you are unlucky enough to
have such a computer then you must first ensure you have fast
enough mainboard RAM. Depending on the mainboard, this can
grow into quite a soldering job. Unforunately this is a broad topic
and goes beyond the scope of this manual. If you can't ensure
the mainboard has fast enough RAM then we advise against
installing the PAK. If necessary, an experienced friend may be
able to help you. Unfortunately we cannot offer this service
since the procedure is far too expensive for anyone to want to
pay... However, it is important to note that for the installation of
a memory expansion if you take the power supply from the
vicinity of the RAM on the mainboard then you should bridge the
built-in Atari choke which seperates the RAM-Vcc section of the
mainboard from the rest.